1. Field of the Invention
The present invention relates to switches, and, particularly, to foot actuated switches.
2. Description of the Related Art
During a dental procedure, a dentist's hands are positioned in or around a patient's oral cavity. For example, the dentist's hands may grasp a dental mirror, dental drill, suction tube, or other dental instrument in order to use the same during the procedure. As a result, the dentist's hands are unavailable to activate the dental instruments or otherwise operate the same. For example, if a dental procedure requires the use of a dental microscope, the dentist may lack a free hand to adjust the focus and/or zoom of the microscope. Moreover, the number of dental instruments that must be used during a dental procedure often require that a dental assistant, who is present during the dental procedure, also holds or otherwise manipulates additional dental instruments.
In order to provide the dentist with an effective way to activate and control a dental instrument when the dentist's hands are unavailable, foot switches have been used. Commonly, these foot switches are formed as an inclined plate with a flat base. The heel of the dentist's foot is placed on the floor and/or the flat base and the toes are lifted above the heel to activate the foot switch. In some embodiments, the inclined plate itself functions as a first switch and additional switches are placed upon the face of the inclined plane. Thus, by depressing one of the switches on the inclined plate, a first function is achieved. Similarly, by depressing the inclined plate itself, a second function may be achieved.
For example, foot switches may be used in conjunction with a microscope to control the zoom of the microscope, as working under microscope magnification is restrictive in many ways. Specifically, under microscope magnification, the depth of field is very shallow and gets shallower as the magnification level is increased. In order to keep a point of interest in focus and maintain a sharp view of a non-stationary three-dimensional operating field having several inclined planes, the microscope must be focused constantly. Otherwise, the operator would have to work in a field that is not in sharp focus until the operator can no longer readily differentiate objects in the operating field. At that point the operator is forced to interrupt the procedure to manually refocus the microscope. With a foot switch controlling a motorized focusing function of the microscope, the operator can maintain sharp focus during the procedure with decreased interruption. Maintaining visual acuity during an operation improves the efficiency of and maintains a higher level of accuracy for a procedure. Further, controlling the zoom function of the microscope with a foot switch allows the operator to either expand the size of the operating field, which may be necessary when an instrument is approaching the edge of the field, or zoom in to see more details with a decreased amount of interruption to the procedure.
While known foot switches are effective, several drawbacks remain. Specifically, because the inclined plate is itself a switch, the dentist's foot must be entirely removed from the inclined plate when it is not being depressed to prevent the dentist from unintentionally altering the function of a dental instrument. As a result, when the dentist attempts to depress any of the switches on the inclined plate, the dentist may need to make visual contact with the inclined plate in order to realign the dentist's foot with the switch. However, making visual contact may be difficult, as the inclined plate is often positioned beneath the patient's head and/or body when the patient is in a reclined position during a dental procedure. Thus, the dentist may need to bend, twist, or otherwise substantially move their upper body to make visual contact with the switch. This results in the dentist having to remove the dental instrument from the patient's oral cavity and stop the progress of the dental procedure in order for the dentist to make visual contact with the inclined plate and to realign the dentist's foot with the switch.
Additionally, since there is nothing that facilitates the retention of the inclined plate and base in position, the inclined plate and base may move as a result of a switch being depressed. Thus, over the course of a dental procedure, the inclined plate and base may move a substantial distance. As a result of this movement, the dentist may again need to make visual contact with the inclined plate in order to realign the dentist's foot with the switch. However, for the same reasons identified above, this causes the dentist to pause or otherwise stop the dental procedure.
Further, if the dentist attempts to keep their foot in position and lifted from the inclined plate of the switch, the dentist is forced to hold their foot in an unnatural position in which the ball and toes of the foot are elevated relative to the heel of the foot. For example, the dentist may maintain the heel on the floor adjacent to the inclined plate with the ball and toes of the foot elevated above the heel and the inclined plate. However, maintaining the foot in this type of position may result in substantial stress and fatigue on the dentist's ankle and/or foot. Moreover, when the dentist attempts to control multiple functions of a piece of dental equipment with a single foot control unit, e.g., an inclined plate that includes multiple switches, the dentist may have to move the dentist's foot between multiple positions to align the foot with the different switches. This gross movement of the dentist's foot may be transmitted through the body and into the hand of the dentist that is holding the dental instrument. Any uncontrolled movements of the body and/or the hands of a dentist during a dental procedure, particularly when being viewed under microscope magnification, may cause an unwanted interruption of the dental procedure.